IBM BPM, V8.0.1, All platforms > Create processes in IBM Process Designer > Modeling processes > Use external implementations

Create an external implementation

Create an external implementation in the Designer view when you want to reuse an existing external application or create an external application to handle one or more steps in your process.

Using the external implementation function is similar to using the service functions like the integration service or web service. However, unlike those service functions that are designed for a specific area like web services or integration, the external implementation is more generic in nature. When a step in a business process is implemented with an external implementation, the business process halts and waits for input from the external application.

To create an external implementation, use the Web APIs or REST APIs. The previous topic discusses a sample that creates an external implementation with the Web APIs. To create an external implementation with the REST APIs, these articles are helpful. Use the REST APIs in IBM BPM and

Integrating a business process application with an external system using the REST API. The related links at the bottom of this topic link to more information on the Web APIs and REST APIs.

When you create an external implementation in the Designer view in IBM Process Designer, you need to know the properties to use to identify and run the custom application. If you did not build the custom application, you need to coordinate with the developers to ensure that you provide the appropriate properties in IBM Process Designer.

Procedure

1. In the Designer view, click the plus sign next to Implementation and select External Implementation from the list of components.
2. Supply a descriptive name for the new external implementation.

3. Click Finish.

4. In the Common section of External Implementation, optionally provide a description in the Documentation text box.

5. In the Custom Properties section, specify the properties to identify and run the external application.

   For example, for an external Eclipse RCP application, you might add custom properties to pass the Java Class name of the form to use for an activity or an application-specific identifier to look up the implementation by another means. Alternatively, you might use the external application name or system ID to find the implementation.

   You can create parameters with a special meaning.

   For example, suppose you need to pass a URL address as a custom property? In the Custom Properties section you could use url as the name and then add a value that is the URL itself (http://mysite.com...).

   You can also use this section to pass data to variables in a client that were instantiated with a constructor.

   You can add custom properties to pass static metadata about the implementation to the external application. For dynamic data, which would be different for each process instance or environment, use the Parameter Details section as outlined in the following step.

6. In the Parameters section, add the parameters for the external implementation by clicking Add Input or Add Output.

   For example, if the external implementation provides an interface in which a manager can either approve or reject an expense report, it might include input parameters for the expense report data and output parameters for the decision that the manager makes and the justification for his decision.

   Be sure to account for all process data that the external implementation requires to complete successfully and also for any data required from the external activity by subsequent activities.

7. Click Save in the main toolbar.

What to do next

You can use an external implementation with Process Portal. In the Custom Properties section add the URL for Process Portal as shown earlier. In the article, Load External Activity URLs from Teamworks Portal, you will see how to retrieve a task ID from the business process to work with a specific task.

Use external implementations

Previous topic: Building a custom application to implement an activity

Next topic: Use an external implementation to implement an activity

Related information:
Developing using the web service API
Developing client applications that use IBM BPM REST APIs